Patella

Patella by Dr Bipul Borthakur

1. PATELLA B y: Dr.Bipul Borthakur Professor, Dept of Orthopaedics, SMCH

2. INTRODUCTION The patella (knee-cap) is located at the front of the knee joint, within the patello -femoral groove of the femur. It’s superior aspect is attached to the quadriceps tendon, and inferior aspect to the patellar ligament. It is classified as a sesamoid type bone It is the largest sesamoid bone in the body.

3. The Patella is seen in the tendon of quadriceps femoris . It is situated in front of the knee joint, thus it’s also termed as ‘knee cap’ Its anterior aspect is convex and rough. Its posterior surface presents a large articular surface split into small medial part and large lateral part. The mechanical function of patella is to hold the entire extensor ‘strap’ away from the centre of rotation of the knee ,thereby lengthening the anterior lever arm and increasing the efficiency of the Quadriceps

4. ANATOMICAL POSITION AND SIDE DECISION Hold the patella in the position that: Its apex faces downward and its base faces upward. Its articular surface faces posteriorly . The large lateral part of articular surface determines the side. Keep the articular surface of patella on the table-top in this manner that its base is directed toward you and its apex far from you. Now find the tilt of patella. The patella, usually, constantly tilts toward the side it belongs to.

5. Functions The patella has two main functions: • Leg extension – It is an integral part of extensor mechanism of knee joint. Protection – Protects the distal part of femur from direct trauma. De-acceleration mechanism of patella help a person to de-accelerate quickly without difficulty while running/in motion.

6. PATELLA FRACTURES MECHANISM OF INJURY : Direct injury : occurs in direct trauma to patella. Eg.fall onto the knee or a blow/ hit directly on the knee. Indirect inury : occurs by a sudden violent contraction of the quadriceps muscle. This usually results in a transverse fracture with a gap between the fragments.

7. PATELLA FRACTURE CLINICAL FEATURES : Swollen and painful knee Abrasions and bruising Tenderness over patella A gap can be felt TYPES OF PATELLA FRACTURES ; Transverse Longitudinal Polar Stellate Comminuted Marginal Osteochondral fracture Longitudinal split

8. PATELLA FRACTURE XRAY VIEWS LATERAL AP SKYLINE

9. TREATMENT UNDISPLACED OR MINIMALLY DISPLACED FRACTURES: When the gap is <2mm or a stellate fracture. Extensor mechanism is generally intact and treatment is mainly protective. A plaster cylinder or an extensor brace is applied Quadriceps exercises has to be practised daily

10. Cylinder plaster and extension brace

11. TREATMENT DISPLACED FRACTURE; The lateral expansion is torn and entire extensor mechanism is disrupted. Surgery is essential: open reduction and internal fixation with (TBW)Tension Band Wiring . Grossly comminuted fracture may require patellectomy .

12. TBW

13. THANK YOU....